Electric cable and conductor



(No Model.)

W. W. JACQUES.

. Electric Cable and Conductor. No. 242,651. Patented June 7,1881.

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UNITED STATES PATENT OFFICEO WILLIAM \V. JACQUES, OF BOSTON, MASSACHUSETTS.

ELECTRIC CABLE AND CONDUCTOR.

SPECIFICATION forming part of Letters Patent No. 242,651, dated June '7, 1881.

Application filed April 25, 1881.

provemcnts in Electric Cables and Conductors,

of which the following is a specification.

My invention relates to IIHIHOVQIHOLHS in electrical conductors, and its object is to enable neighboring conductors to be used at the same time for electrical signals without sorious disturbance from one another.

When two or more conductors of electricity are placed near together, as in a cable or otherwise, every signal transmitted over one by the *ariations of the electrical current will produce in the others corresponding currents, which more or less disturb and interfere with the use of the others for separate and distinct signals, even when each conductor is so perfectly insulated that absolutely no electricity passes from one to another. In the use of such conductors for any very delicateinstrumentrequiringrapid changes of the current-such, for example, as atelephone-this disturbance becomes asource of serious annoyance and inconvenience, even in cables of moderate length, for such instrtr ments, being of necessity made sufficiently sensitive to be affected by the very minute currents which operate upon them, are clearly subject to be influenced by very slight external or foreign currents.

In Letters Patent granted to Dr. Alfred Faucaut, May 18, A. D. 1869, No. 90,089, for improvement in cables, is described one method for preventing this annoyance.

Figures 1 and 2 of the drawings show one conductor of a Fa-ucaut cable, with its lateral dimensions much enlarged for convenience of representation.

The letter (t represents the conductor; I), the insulating material, such as gutta-percha, kerite, or fiber of cotton or other substance impregnated with any suitable insulating compound.

a is an envelope or sheath of a conducting material, conveniently made of metal foil, with a rather fine copper Wire wound spirally around it. This conducting-envelope is connected to the ground at suitable intervals, (1 cf, by the conductors shown. Several of these protected conductors are made into a cable inclosed in a (No model.)

suitable protective covering, as in Fig. 3. \Vhcn a signal is made and the signaling-cue rent begins to flow and ceases to flow, or increases and diminishes in the conductor a, electrical changes are produced in the sheath 0. For example, the potential is raised at the point e, and this gives rise to a current which flows around the circuit formed by the envelope c, the ground wire c, the earth, another ground-wire, (I or f, and back to the envelope, and thus the electrical equilibrium of the envelope is restored. In order that this operation may proceed with ease and efliciency, itis essential that the circuitover which this equating current flows shall be of small total resistance, and in practice it is found desirable to obtain this small resistance by connecting the conductirig-envelope to the ground, with short intervals of space between the connections d cf-for example, of from one hundred to three hundred feet.

A convenient way of frequently grounding the conducting-envelope and of diminishing the resistance of theequating or compensating circuit is described in Letters Patent granted to Charles E. Ohinnock, No. 224,579, hearing date of Februaryl'i ,1880; butthe conductingenvelope 0 is very close to the conductin g-wire a, and its intimate electrical connection with the earth, or with any other infinitely large conducting mass of matter, by frequent connectin g-wires, introduces the difficulty of retardation or sluggishness of signals. \Vhen such a conductor is used, grounded at such intervals as are found desirable to prevent inductive disturbances, the sluggishness thus caused will in a few miles of cable so blur the rapid signals upon which the operation of the speakingtelcphone depends that the actual action at the receiver becomes much enfeeblcd, and the signals are given indistinctly, or are rendered altogether unintelligible.

The object of my invention is to remedy this evil. To that end, instead of grounding the outer envelope by connecting the wires d c f to the ground, as in Fig. 1, I carry them to an insulated conductingwirc, g h, Fig. 4. Thisis made of low resistance, and thus affords a circuit of low resistance, while at the same time its inconsiderable size and capacity obviates the difficulty of sluggishness due to the connection with the great mass of the earth, as shown in Fig. 1, and as heretofore practiced.

I will describe one cable with which I have obtained good results, both as regards distinctness of articulation and freedom from inductive disturbances and interfering signals when the other wires in the same cable were used telephonically, without, however, intending to confine myself to this special process, form, or dimensions.

Fig. 4 represents one insulated conductor of this cable with its metallic conductor connected at intervals to the equating-wire. In this cable the conductor a used for the signaling was a copper wire of No. 20 gage, covered with an insulating or non-conducting material, I), to No. 10 gage. This was wrapped with metal foil 0, around which a copper wire of No. 80 gage was wound spirally. The wires cl ef were copper wires of No. 20 gage and a few inches long, applied at intervals of one hundred feet. The wires 9 it gave a resistance of .03 ohms per hundred feet.

In the case of an overhead cable hung from a suspending-wire, as is often practiced, it is obvious that such suspending-wire, if properly insulated, may be used for the equatingconductor 9 h. The conductorg It may also be strapped to the exterior of the cable, and even included in the same protecting-envelope, pr0- vided that itis suitably insulated from the conducting envelope 0, except at the points designated d c f; or the armor of a cable can be used for the equalingeonductor it' insulated from the earth.

All the conducting-envelopes may be con nected with one and the same erpiating-conductor, and preferably would be, instead of.

or wires, in combination with the equating- I conductor, insulated from the earth and connected to said conducting-envelope by means of electrical connections placed at intervals, as and for the purposes set forth.

2. An electrical cable or group of electrical conductors consisting of signal or main line conductors, each surrounded by an insulating covering and incased in a conducting envelope or sheath connected atintervals with an equating-comlnctor of small ma s and capacity, substantially as set lorth.

3. The hereinbetore-described method of obviating or preventing both retardation and induction in electrical cables or conductors by connectingtheconductirig-sheath surrounding the insulated signal-condnctor in such cables to an equating-wire or similar conductor at suitable intervals, substantially as set forth.

In testimony whereofI have signed my name to this specification, in the presence ot'two subscribing witnesses, this 20th day of April, AV I). 1881.

' WILLIAM \V. JACQUES.

Witnesses:

J. B. HENCK, Jr., T. l). LOCKWOOD. 

